4 a - Introduction - jaw relation
- 3. Dr. Amal Fathy Kaddah Professor of Prosthodontics Faculty of Dentistry Cairo University
- 4. the end If it's not okay, then it's not the end
- 5. • The stomatognathic system • What 'occlusion' is and why it is important • Definitions. • The significance of 'ideal occlusion‘ • Difference between natural and artificial Occlusion. • Mandibular Movements. • Articulators and Facebows. • Balanced Occlusion and Factors affecting Balanced Occlusion. • Concepts of occlusion (Balanced and Non balanced Occlusion). • Recording of Occlusion for removable prosthodontics. • Occlusal correction for Removable Prosthesis. • Occlusion and implant restorations (Loading protocols) Occlusion Outline
- 6. Maxillomandibular Relationship Any spatial relationship of the maxilla to the mandible The Glossary of Prosthodontic 2005 jaw Relation
- 7. Clinical significance of jaw relation
- 8. • Re-establish the functional position of the mandible • Maintaining the stability of complete dentures, with the least amount of trauma to the supporting tissues. • Esthetic and functional efficiency. • Preservation of the remaining structure. • Comfort
- 10. Stomatognathic System • The movement of the jaw is orchestrated OR organized by a very complex set of muscles, which are in turn controlled by the body's local and central nervous system Stoma = Mouth Gnathion = jaws
- 11. The stomatognathic system = the masticatory system = • Teeth • Periodontium • Jaws • TMJ • Associated muscles of tongue & muscles of the soft palate • Investing tissues • Neural control
- 12. Muscles of Mastication: Neuro Muscular System Masseter Temporalis Lateral Pterygoid Medial Pterygoid Tempromandibular Sphenomandibular Stylomandibular TMJ and T M Capsule Associated Ligaments
- 14. Bilateral joints permit the mandible to move as one unit with two functional patterns: - Hinge (inferior portion) - Translation (superior portion)
- 16. 1- The Condyles 2- Articular disc 3- The joint capsule 4- Articular Fossa (surface of the temporal bone) 5- Temporomandibular ligament 6- Masticatory Muscles The main components are
- 17. Condyle: The rounded articular surface at the end of the mandible (lower jaw). Glenoid fossa: A deep concavity in the temporal bone at the root of the zygomatic arch that receives the condyle of the mandible Tubercle: A slight elevation from the surface of the bone giving attachment to a muscle or ligament.
- 18. Articular disk is a thin, oval fibrous connective tissue plate, non-vascular, placed between the condyle of the mandible and the mandibular fossa. Its upper surface is concavo-convex and Its under surface, is concave, to accommodate and adapt itself to the form of the mandibular fossa and the articular tubercle. Able to tolerate forces, It divides the joint into two cavities, each is provided with a synovial membrane.
- 19. Biconcave articular disc C.T. capsule • Capsule: Dense fibrous connective tissue, Provides protection to condyle and fossa during movements • Lacks blood vessels and nerves • Able to tolerate forces without damage or pain being produced
- 20. The Synovial fluid: Consist of small amounts of a clear, straw-colored viscous fluid. It is an infiltrate of the blood diffused out from the rich capillary network of the Synovial membrane. Function: 1- Lubrication 2- Nutrition. 3- Clear the tissue debris.
- 21. TMJ LIGAMENTS AND CAPSULE Yellow Stylomandibular Ligament Red Pterygomandibular raphe Green Sphenomanibular ligament
- 22. Muscles of Mastication: Masseter Temporalis Lateral Pterygoid Medial Pterygoid Anterior belly of digastric Mylohyoid muscle Geniohyiod muscle Accessory muscles of mastication
- 23. The mandible opens, and while initiating closing, there is a shift slightly to the side of the bolus, due to the oblique orientation In normal chewing function of the masseter and medial pterygoid.
- 24. The closure of the mandible does not occur in a straight upward movement but rather in a curve
- 25. Elevation of mandible (closes the jaw) Masseter Temporalis Elevation of the mandible (closes the jaw) Assist in Retrusion of mandible Assist in protrusion of mandible • Elevation of the mandible (closes the jaw) • Minor contribution to protrusion of the mandible • Right medial pterygoid with left lateral pterygoid turn the chin to left side Medial Pterygoid Wikipedia
- 26. • Protrusion of the mandible: The primary function of the lateral pterygoid muscle is to pull the head of the condyle out of the mandibular fossa along the articular eminence to protrude the mandible. • Jaw opening (Depresses the mandible) it is assisted by the digastric, mylohyoid and geniohyoid muscles. • SIDE TO SIDE movements GRINDING MOVEMENT • Unilateral action of a lateral pterygoid produces contralateral excursion (a form of mastication), usually performed in concert with the medial pterygoids. Lateral Pterygoid Wikipedia
- 27. The primary function of the lateral pterygoid muscle is to pull the head of the condyle out of the mandibular fossa along the articular eminence to protrude the mandible. Protrusion of the mandible
- 28. the Digastric muscles is not a muscle of mastication but it play an important role in mandibular function The Lateral Pterygoid muscles open the mouth (depressing the mandible), with the assistance of the Digastric muscles
- 29. The Lateral Pterygoid muscles move the condyles laterally (from side to side)
- 30. IF YOU CAN’T FEED A HUNDRED PEOPLE THEN JUST FEED ONE
- 32. 1. Orientation relations (Occlusal plane orientation) 2. Vertical relation, and 3. Antero - posterior relation Three - dimensional record Boucher classified jaw relations into three groups
- 33. 1- ORIENTATION RELATION Orient the mandible to the cranium in such a way that when the mandible is kept in its most posterior position, the mandible can rotate in a sagittal plane around an imaginary transverse axis passing through or near the condyles. THE AXIS CAN BE LOCATED BY THE FACEBOW.
- 34. • ORIENTATION OF MAXILLA IN RELATION TO BASE OF SKULL Plane of maxilla may be tilted in some patients, in such cases plane of mandible will not be altered since it articulates with base of the skull. Hence, a maxillary tilt will alter the relationship of maxilla to mandible during different movements, also affect the level of occlusal plane.
- 35. • Orientation of occlusal plane • The occlusal plane is defined as “the average plane established by the incisal and occlusal surfaces of the teeth".
- 36. • Importance of orientation of occlusal plane Anteriorly, occlusal plane mainly helps in achieving esthetic & phonetic. posteriorly, it forms a milling surface, where tongue & buccinator muscle are able to position the food bolus onto it , and hold it there during mastication. Incorrect of occlusal plane would hamper esthetics, phonetics, & mastication. It may affect stability of complete denture & ultimately result in alveolar bone resorption.
- 37. 1. Protrusive relation, 2. Right lateral relation, and 3. Left lateral relation
- 39. Recording Jaw Relations Occlusal plane & Facial Contour Horizontal Relation Eccentric jaw relation Vertical Relation Recording Jaw Relationships
- 40. When you realize you've made a mistake, take immediate steps to correct it.
- 42. The STATIC relationship between the incising or masticating surfaces of the maxillary and mandibular teeth, or tooth analogues.
- 43. The contact relationship between the occlusal surfaces of teeth during function. It is the DYNAMIC contacts relationship of the teeth as the mandible moved to and from eccentric relation.
- 44. Movement occurring when mandible moves away from maximum intercuspation Undesirable contacts occurring during lateral movements
- 45. The side toward which the mandible moves in a lateral excursion Working side
- 46. Non working (balancing) side The side which the mandible moves toward the median line in a lateral excursion
- 47. The most retruded relation of the mandible to the maxillae when the condyles are in the most posterior unstrained position in the glenoid fossae
- 48. The relation of the mandible to the maxilla with the mandible in its most retruded position. (GPT) 2005
- 49. Dawson has defined this position as the rearmost, uppermost, midmost (RUM) position of the condyle in the fossa at which the medial pole of the condyle disc assembly is braced against the bony wall of the eminentia.
- 50. Whatever is the definition of centric relation it is reproducible, stable and functional position. The rearmost, uppermost, midmost (RUM) position of the condyle in the fossa The most posterior unstrained position in the glenoid fossae The uppermost and rearmost position in the glenoid fossae The anterior-superior position against the articular eminences
- 51. The mandible is in centric relation if four criteria are fulfilled: 1.The disk is properly aligned on both condyles. 2.The condyle-disk assemblies are at the highest point possible against the anterior slopes of' the eminentiae. (Uppermost) 3. The medial pole of each condyle-disk assembly is braced by bone. (midmost) 4.The inferior lateral pterygoid muscles have released their contraction and are passive (most posterior unstrained position)
- 52. Is the only constant repeatable position within the functional limit to start constructing a stable occlusion
- 53. Maximum Intercuspation: The complete intercuspation of the opposing teeth independent of condylar position
- 54. CENTRIC OCCLUSION The occlusion of opposing teeth when the mandible is in centric relation, This may or may not coincide with the centric relation in natural dentition GPT 9
- 55. Centric Occlusion: Static contact relationship that exist after the jaw movement has stopped and the tooth contact are identified
- 56. • In 90% of individuals with full complement of natural teeth, maximum intercuspation, does not coincide with centric relation of the jaws. • In most patients centric occlusion is located anterior to the centric relation by 0.5-1.5 mm measured in the horizontal plane.
- 57. In the edentulous patients, use the posterior border position (CR) Centric Occlusion made to coincide with CR
- 58. Long centric or Freedom in centric The occlusal surface of the teeth could be altered to allow freedom of tooth movement in harmony with the rotation of condyle. (from hinge position to habitual intercuspal position).
- 59. Anterior Contacts in MI and posterior point is the COR Long centric or Freedom in centric
- 60. Centric occlusion with teeth present is a tooth to tooth relation whereas centric relation, is a bone to bone relation (Static positions)
- 61. Eccentric Occlusion: Static occlusion other than centric occlusion: Protrusive occlusion and Lateral occlusion
- 62. The vertical dimension of the face when teeth are in maximal intercuspation.
- 63. • The distance measured between two selected anatomic or marked points (usually one on the tip of the nose and the other one on the chin) when occluding members are in maximal intercuspation. GPT 9
- 64. Occlusal vertical dimension The distance measured between two points when occluding members are in contact and condyles are in centric relation.
- 65. Inter-alveolar distance inter-ridge distance • The vertical distance between specified positions on the maxillary and mandibular alveolar ridges at the occlusal vertical dimension.
- 66. The vertical dimension of the face when the mandible is in rest position.
- 67. • The space between the maxillary and mandibular occlusal surfaces when the mandible is in the rest position. when the mandible is in a specified balanced position, it ranges from 2-4 mm.
- 68. • Isometric contraction It is contraction of muscle without shortening Elevator muscles. Contract isometrically to keep the mandible at rest (tension without shortening) Ring of closing, opening and post vertebral muscles.
- 69. V D R V D O = V D R - F W S V D O 2 to 4 mm.
- 70. Hinge Axis • A transverse axis about which the mandible can rotate without translatory movement of the condyles. Hinge Movement • An opening or closing movement of the mandible about the hinge axis.
- 71. This relation exists when the jaws are in centric relation and the teeth are in centric occlusion To obtain a centric relation record it is necessary to determine the vertical dimension of occlusion.
- 72. State of equilibrium of the denture bases in relation to their supporting structure. when the opposing teeth contact.
- 73. Balanced Occlusion • Simultaneous contacts of the occluding surfaces of the teeth in various jaw positions. Free Articulation = Balanced Articulation = Unobstructed Articulation • Articulation that is unobstructed by cuspal interference. • Simultaneous contacts of the occluding surfaces of the teeth during function The Glossary of Prosthodontic 2005
- 74. Balanced Occlusion/Articulation •The Bilateral simultaneous contact of the anterior and posterior teeth in excursive movements. (GPT 9)
- 75. Christensen’s phenomenon • A gap occurring in the natural dentition when the mandible is protruded. It can lead to instability in full dentures unless compensating curves are incorporated into the dentures.
- 76. Bonwill’s Triangle The distance between the center of each condyle and the contact point of the two lower central incisors form an equilateral triangle (4 inches=10 cm length) which does not change throughout life. This triangle is established as the Bonwill triangle.
- 77. • V ARIATIONS IN THE SIZE of Bonwill’s triangle influence the cusp angulation for complete dentures. Bonwill’s Triangle • He found that the dimensions of the teeth and other cranial bones and even the whole body are in constant relation to the length of the sides of this triangle. • Construction of average articulators is generally in accordance with Bonwill’s theory,
- 78. • As a result of his jaw measurements Bonwill developed in 1864 the first Bonwill articulator, a device for simulating the temporomandibular joint movements for manufacturing dentures. Bonwill’s Articulator
- 79. In Summary 1. What 'occlusion' is and why it is important 2. The stomatognathic system 3. Clinical significance of jaw relation 4. Retruded Jaw Relation, Centric Jaw Relation, Centric Relation 5. why occlusion is important 6. Denture Stability 7. The stomatognathic system 8. Centric and Eccentric occluding relation 9. Vertical dimension of occlusion 10.Vertical dimension of rest 11.Interridge distance 12.Free way space, inter occlusal distance 13.Balanced Occlusion and Free Articulation 14.Hinge Axis and Hinge Movement 15.Christensen’s phenomenon 16.Bonwill’s Triangle
- 80. نـفــع إن بعلمي حـسبي الطمــع في إال الــذل ما من رجــــع هللا راقـب .. وارتفــع طير طــار ما وقــــع طـار كـما إال